Proximal Junctional Kyphosis in Adolescent Idiopathic Scoliosis After 3 Different Types of Posterior Segmental Spinal Instrumentation and Fusions

Abstract

Two-year postoperative PJK prevalence in AIS following 3 different posterior segmental spinal instrumentation and fusion surgeries was 27%. A larger preoperative thoracic kyphosis angle, greater immediate postoperative thoracic kyphosis angle decrease, thoracoplasty, and male sex correlated significantly with PJK. There were no significant differences in Scoliosis Research Society Patient Questionnaire-24 outcome-scores between the PJK and non-PJK group.

Combined Anterior-Posterior Surgery is the Most Important Risk Factor for Developing Proximal Junctional Kyphosis in Idiopathic Scoliosis

“…One of the complications that can occur after arthrodesis in spine fusion is proximal junctional kyphosis (PJK) [2][3][4][5][6][7][8][10][11][12][13]. PJK is the progression of kyphosis at the proximal end of a construct greater than 10°, which can lead to progressive decompensation in the sagittal plane and, in some cases, neurologic compromise [2].…”

“…PJK is the progression of kyphosis at the proximal end of a construct greater than 10°, which can lead to progressive decompensation in the sagittal plane and, in some cases, neurologic compromise [2]. The reported incidence ranges between 10% and 40% [2,[5][6][7][8][9][10][11][12][13]. Reported risk factors for developing PJK include long rigid fusion constructs [2,5], integrity of the posterior soft tissue tension band [2], instrumentation techniques [3,7], magnitude of sagittal balance correction, and bone quality [12].…”

Reply to Letter to the Editor: Combined Anterior-Posterior Surgery is the Most Important Risk Factor for Developing Proximal Junctional Kyphosis in Idiopathic Scoliosis

“…One point mentioned by Dr. Yoshihara is that pedicle screw instrumentation damages the supraadjacent facet capsule owing to the footprint of the screw head. Although I agree this is theoretically possible, this has not been supported consistently in the literature [2,4,7,10]. If this were true, one would expect constructs using hooks at the upper instrumented vertebrae to have lower rates of PJK.…”

“…More recent literature comparing PJK rates in those with upper thoracic (T1-T3) versus lower thoracic (T10-T12) instrumented vertebrae [4,8] have determined that upper instrumented vertebrae in the lower thoracic spine had a higher PJK rate. In addition, some studies [4][5][6][7][8] have failed to show a difference in PJK rates between different upper instrumented vertebrae.…”

“…If this were true, one would expect constructs using hooks at the upper instrumented vertebrae to have lower rates of PJK. In fact, reports are inconsistent when it comes to instrumentation type at the upper instrumented vertebrae and PJK, with one report [2] showing a difference and others [4,7,10] showing no difference whether a pedicle screw or a hook is used at the upper instrumented vertebrae.…”